Koyana Wildlife Sanctuary located in Satara district in western Maharashtra, covers an area of 423.55 sq km. This sanctuary lies at the southern end of the Sahyadri sub-cluster between longitude 73o33' E to 73o51' E, and latitudes 17o 21'N to 17o 46'N. Elevation ranges from 600-1,100 m (MoEF 2006). The mean annual rainfall in the sanctuary is 2,500 mm with a maximum of 5,000 mm of rainfall being recorded. The sanctuary is fed by three rivers-Koyna, Kandati and Solashi. This protected area includes the eastern and western catchments of Koyna dam and the Shiv Sagar reservoir. The sanctuary is an important ecological corridor since it forms a continuous link with Chandoli National Park and Radhanagari Wildlife Sanctuary (MoEF 2006).

The forest types seen here are southern tropical evergreen forests and southern moist mixed deciduous forests (Champion and Seth 1968). Tree species dominating the landscape here include mango (Mangifera indica), ironwood tree or anjani (Memecylon umbellatum), Javan plum or jamun (Syzigium cumini), hirda or chebulic myroblalan (Terminalia chebula) and pisa (Actinodaphne angustifolia). Others like different species of Acacia, Ficus and Phyllanthus too can be distinctly spotted in the forest canopy. Endangered species endemic to the Western Ghats like longan (Euphorbia longan), Elaeocarpus tectorius, Mappia foetida, and giant trees like Harpullia arborea, Scolopia crenata and Turpunita malabarica and woody climbers like St. Thomas bean (Entada scandens) are also found here. The moist forests stretch on right up to the river boundaries where they overlap with the dry forest tracts, thus forming interesting riparian corridors for wildlife (MoEF 2006).

The forests of this protected area provide a good habitat for tigers (Panthera tigris), leopard cats (Prionailurus bengalensis), Indian bison or gaur (Bos gaurus), sloth bears (Melursus ursinus), sambar (Cervus unicolor), barking deer (Muntiacus muntjak), mouse deer (Moschiola meminna), Indian giant squirrels (Ratufa indica) and common langurs (Semnopithecus entellus) (Jathar et al. 2004). Like Radhanagari Wildlife Sanctuary, this protected area too has a large number of gaur and a census carried out by the Kohlapur Wildlife Division in 2004 estimated the gaur population to have risen from 435 to 493 (PA Update 2004). An earlier census in 2002 had also reported a increase in gaur population in addition to that of tiger, leopard (Panthera pardus), barking deer, mouse deer, sloth bear and blackbuck (Antilope cervicapra) (PA Update 2002).

From an ornithological perspective, no systematic study has been done in this sanctuary. In an environment impact assessment study carried out by the Bombay Natural History Society as many as 61 species of birds have been reported from this sanctuary including Himalayan birds like the Indian blue robin (Luscinia brunnea) (Jathar et al. 2004) .

Reptiles seen here include the Indian rock python (Python molurus), Beddome's keelback (Amphiesma beddomei), Indian chameleon (Chamaeleo zeylanicus), a subspecies of the Deccan banded gecko (Geckoella decaanensis) and the dwarf gecko (Cnemaspis sp.). Amphibians endemic to the Western Ghats like the Koyna toad (Bufo koyanansis), wrinkled frog (Nyctibatrachus sp.) and the Bombay bush frog (Philautus bombayensis) can also be seen here (Giri 2003, personal communication cited by Jathar et al. 2004).

Privately owned forests and patches of agricultural land scattered across the sanctuary are a major disturbance to the biodiversity of this protected area. Since the area is already a popular trekking spot and is also being promoted as a tourism zone by the Maharashtra government, littering of non-biodegradable waste, noise pollution and water pollution are other serious disturbances (Jathar et al. 2004). Besides this, strong winds in the area have led to many windmills being set up near the sanctuary. Windmills are especially dangerous to the bird population, which are at risk of getting injured or killed by the blades. Over-exploitation of the sanctuary's rich medicinal plant sources poses a grave threat to the medicinal plant biodiversity of this region. Other serious threats to the forests and wildlife of this sanctuary include, poaching, setting up of dams and hydroelectric projects like the Humbardli Pumped Storage Schemes (Jathar et al. 2004).

References

Champion, H.G and Seth, S.K. 1968. A revised survey of forest types of India. Government of India Press, Delhi, India.

Jathar, G., Giri, V and Akhtar, A. 2004. Koyna Wildlife Sanctuary. In: Important Bird Areas in India: Priority sites for conservation. (eds Islam, M. Z and Rahmani, A. R).Indian Bird Conservation Network: Bombay Natural History Society and Birdlife International, UK. pp 708-709

MoEF. 2006. India's Tentative List of Natural Heritage Properties to be inscribed on the UNESCO World Heritage List. UNESCO, Paris, France.

PA Update. 2003. Forest land diverted for resettlement of villagers from Koyna WLS. April (41&42).